1. Field of the Invention
The present invention relates to the cutting of mortises in wood or other materials having similar machining characteristics by a powered tool and more particularly, to an improved adapter for converting a conventional radial arm saw to a mortising machine tool.
2. Description of the Related Art
A radial arm saw mortising adapter is disclosed in U.S. Pat. No. 4,470,438. This adapter utilizes a base plate to which a chain saw blade and chain saw can be attached. The base plate includes a fixed clamp bracket to which a clamp cap is bolted for clamping the mortising adapter to the housing of a radial arm saw. A driving spindle includes a hexagonal socket which fits over the hexagonal section of the radial arm saw arbor. The driving spindle is connected by a belt drive to a driven spindle which drives the chain saw. Because the clamp bracket is fixed, the bearing for supporting the driving spindle is mounted in a block which is slideably adjustable in the base plate so that the driving spindle can be adjusted to be concentric with the arbor when the mortising adapter is clamped to the radial arm saw motor. Slack in the drive belt is removed by mounting the bearing which supports the driven spindle in an adjustable eccentric mounting. The chain saw is tensioned by a standard tensioning bolt attached to the chain saw blade.